1. Field of the Invention
This invention relates to fats and oils having superior digestibility and adsorptivity, and more particularly it relates to fats and oils consisting of triglycerides having a short chain fatty acid of C.sub.14 or less at the 2-position thereof.
2. Description of the Related Art
Natural fats and oils include plant fats and oils represented by soybean oil, rape seed oil, safflower seed oil, etc. and animal fats and oils such as beef tallow, fish oils, etc. and they have specific features that the former contains a large quantity of linolic acid as an essential fatty acid, while the latter contains short chain and C.sub.20 or higher highly unsaturated fatty acids such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), etc. In particular, in view of the fact that linolic acid exhibits an effectiveness of reducing serum cholesterol, while EPA and DHA have a function of inhibiting thrombocyte agglutination as well as a function of reducing serum cholesterol and exhibit an effectiveness of preventing brain thrombus, it has been urged that intake of these long chain highly unsaturated fatty acids is important for health maintenance. Thus, use of safflower oil and purified products of fish oils for various foods has been being increasing, but the digestibility and absorptivity of fats and oils containing a large quantity of these fatty acids cannot be said to be so good. In particular, the problem of the digestibility and absorptivity has been becoming more serious for persons emaciated in the digestion function as in patients and old persons.
On the other hand, it has been known that unlike such long chain fatty acids, fats and oils composed only of shorter chain fatty acids of 8 to 12 carbon atoms, i.e., medium chain fatty acid triglycerides, are very rapid in the absorption and also easy in the metabolism; hence they have been used as the lipid source of fluid foods, etc. However, such medium chain fatty acid triglycerides have often caused side effects such as acosmia of alimentary canals such as diarrhea accompanying the rapid absorption and metabolism, formation of ketone substances at the time of intake of a large quantity thereof, etc.
Thus, since it is difficult to use a large quantity of medium chain triglycerides as an energy source, it has been recommended to supplement use medium fatty acid triglycerides with long chain fatty acid triglycerides. As a process for such simultaneous use, a process of merely nixing the both, and a process of mixing the both followed by random ester exchange therebetween, have been proposed. However, these processes are still insufficient in the aspect of digestibility and absorptivity.